Add navigation component tests

[joshuatf]

Description

Adds the navigation component tests.

How has this been tested?

Through...tests.

Testing

1. Run npm run test-unit packages/components/src/navigation
2. Make sure all tests pass.
3. Make sure test coverage is adequate.

[psealock]

Nice @joshuatf, thanks for the added coverage. In 4c846b5 I went through the tests and changed a few things relating to queries and best practices. This is a really good guide https://kentcdodds.com/blog/common-mistakes-with-react-testing-library.

• Use screen instead of container. https://kentcdodds.com/blog/common-mistakes-with-react-testing-library#not-using-screen
• Use getByRole instead of querying for tags or classes. https://kentcdodds.com/blog/common-mistakes-with-react-testing-library#not-using-byrole-most-of-the-time

[psealock]

I also added 2 tests for presence of an href and LinkComponent in a3d444c

[psealock]

🎉 These tests found their first 🐞 introduced in #24878 . Tests were failing due to a null value passed to Button's href. Button has an explicit check for undefined, so the null was causing an anchor tag where it should have been a button tag.

Fixed in aa4ab1f